In the field of dentistry, a technique called “implant overdenture system” for stabilizing an implant overdenture fixed in oral cavity is known. The implant overdenture system provides a structure in which the implant overdenture is fixed onto alveolar ridge by the support of dental implants configured to be inserted in alveolar ridge.
An implant has an implant body configured to be inserted in alveolar ridge, and an implant-side connector attached to an end of the implant body and configured to be exposed to oral cavity.
The implant overdenture is furnished with a plurality of artificial teeth, and a denture base for the plurality of artificial teeth to be fixed thereto. The denture base is structured to cover the alveolar ridge. The implant overdenture further has a denture-side connector in the denture base, and this connector is coupled to the implant-side connector.
As described later, magnetism-mediated coupling and mechanical coupling have so far been disclosed as means for coupling the denture-side and implant-side connectors.
Under the standards set forth in the Pharmaceutical Affairs Law, the implants conventionally used in the implant overdenture systems are generally divided into following types: relatively large implants having a body diameter of 3.0 mm or more and 7 mm or less and generally known as implant, and smaller implants having a body diameter of less than 3.0 mm and generally called “mini-implant”.
Patent Document 1 discloses a technique using the relatively large implants wherein the implant overdenture is fixed to these implants by a magnetic force. The implant-side connector includes a keeper formed from a magnetic material, and the denture-side connector includes a magnetic assembly inserted in the denture base. The implant overdenture is fixed to the implants by making the keeper be attracted to the magnetic assembly by its magnetic force.
Some known implant overdenture systems using the mini-implants are structured to mechanically fix the implant overdenture to the mini-implants. The implant-side connector has a substantially cylindrical shape. The implant-side connector has a head part formed on an edge side thereof, and a fallen groove formed in the border between the head part and the implant body. The denture-side connect or has a cavity including a housing that can accommodate therein the head part, and an O ring provided between the fallen groove and the housing. The head part is located in the housing, and the implant overdenture is then fixed to the mini-implants by a fastening force generated by the O ring.